1. Technical Field
The present invention relates to lens modules, and particularly to a lens module having a focusing function, a lens of the lens module, and a camera module using the lens module.
2. Description of Related Art
Currently, camera modules are in widespread use in a variety of portable electronic devices, such as mobile phones, notebook computers, and personal digital assistants (PDAs). Such camera modules are typically required to have excellent imaging performance, and accurate and convenient focusing functions.
A conventional camera module includes a lens module and an image sensor. The lens module includes at least one lens. The image sensor is positioned in alignment with the at least one lens. The focusing function is usually carried out by a mechanism wherein a distance between the at least one lens and the image sensor is varied. Generally, an actuator such as a step motor is provided to drive the least one lens to achieve the focusing function. However, the step motor is typically quite bulky. In addition, the step motor consumes a substantial amount of power, especially relative to the amount of power that can be stored in a typical battery system that powers the camera module.
What is needed, therefore, is a lens module having a simple and energy-efficient focusing mechanism, a lens of the lens module, and a camera module using the lens module.